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Dissertation
Regulatory Mechanisms of Purinergic Signaling in Plant Growth and Defense
Washington State University
Doctor of Philosophy (PhD), Washington State University
2023
DOI:
https://doi.org/10.7273/000006359
Abstract
Extracellular ATP (eATP) is a crucial signaling element in both animal physiology and plants. Its role as a purinergic signal for plant growth and defense responses is recognized in the plant biology community. However, a lack of P2K1 receptor interactome and limited methodologies for monitoring eATP responses hindered comprehensive understanding of purinergic signaling mechanisms. This thesis explores eATP's role in plant growth and defense responses, with a focus on P2K1's signaling mechanisms. Following Jewell et al.’s ATP-induced transcriptome, we identified five eATP-responsive genes and studied their expression patterns in response to ATP treatment. The findings suggested the root tip as a critical eATP signaling hub. We investigated the IDR in P2K1's C-terminal tail, revealing its pivotal role in converting eATP sensing into root growth regulation. C-terminal tail deletion caused prolonged eATP signaling, leading to ROS accumulation, and altered cell wall integrity in the root meristem, ceasing root growth due to increased cell death—providing further support for the root tip as a hub for eATP signaling through P2K1. We identified phosphorylation sites in the C-terminal IDR which might regulate P2K1 kinase activity by altering the conformation of P2K1’s C-terminal tail. Last, a P2K1- interactomics study uncovered putative interacting proteins, including CPK28, a negative regulator of P2K1-mediated eATP signaling. CPK28 overexpression alleviated eATP hypersensitivity, promoting plant growth, while CPK28 loss led to stunted growth, like P2K1 overexpression. CPK28 also negatively regulated eATP-induced chlorosis during B. cinerea infection. In conclusion, this thesis illuminates eATP's intricate signaling mechanisms in plants, emphasizing P2K1's crucial role and interactions in integrating eATP-sensing into growth and defense regulation.
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Details
- Title
- Regulatory Mechanisms of Purinergic Signaling in Plant Growth and Defense
- Creators
- Joel Martin Sowders
- Contributors
- Kiwamu Tanaka (Advisor)Andrei Smertenko (Committee Member)Cynthia Gleason (Committee Member)John A Browse (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Program in Molecular Plant Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 183
- Identifiers
- 99901087338201842
- Language
- English
- Resource Type
- Dissertation